Kisame is a hard one to decide, we have seen him under so many different circumstances its hard to measure how powerful he is. Half the time he was without his sword because of Bee. Also he lost due to a bad match up with Guy who only uses taijutsu in his last huge attack so the attack couldn't be absorbed by the shark jutsu.
I think Kisame would lose, he just isn't on that level of power. He has lots of chakra but doesn't have many powerful jutsu to use while Onoki has his dust release which is probably same class as a rasen-shurikan or rasengan. Don't talk about his special shark bomb absorbing the dust release, we have only seen him using it when he is in the ocean and I find it hard to believe he can keep spamming it. Also Onoki can fly above all the water and sharks, can't catch him.